• A huge iceberg, the world’s largest, has broken off from an ice shelf in Antarctica and is floating through the Weddell Sea, the European Space Agency said.

• The iceberg, dubbed as A-76, is more than seven times the size of Mumbai, 40 times the size of Paris, or about 73 times as big as Manhattan, making it the largest currently afloat.

• The iceberg is around 170 kilometres long and 25 kilometres wide, with an area of 4,320 sq km. Mumbai, for comparison, is around 603 sq km in area.

• It was first spotted by scientists at the British Antarctic Survey and confirmed by the US National Ice Center using images taken by the European Space Agency’s Copernicus Sentinel-1 mission.

What is an iceberg?

• An iceberg is ice that broke off from glaciers or shelf ice and is floating in open water.

• To be classified as an iceberg, the height of the ice must be greater than 16 feet above sea level and the thickness must be 98-164 feet and the ice must cover an area of at least 5,382 square feet.

• There are smaller pieces of ice known as “bergy bits” and “growlers.” Bergy bits and growlers can originate from glaciers or shelf ice, and may also be the result of a large iceberg that has broken up. 

• A bergy bit is a medium to large fragment of ice. Its height is generally greater than three feet but less than 16 feet above sea level and its area is normally about 1,076-3,229 square feet. 

• Growlers are smaller fragments of ice and are roughly the size of a truck or grand piano. They extend less than three feet above the sea surface and occupy an area of about 215 square feet.

The largest existing iceberg

• The enormity of A-76, which broke away from Antarctica’s Ronne Ice Shelf, ranks as the largest existing iceberg on the planet, surpassing the now second-place A-23A, about 3,380 sq km in size and also floating in the Weddell Sea.

• A-76 does not beat the size of the previous largest iceberg, B-15, which was discovered in 2000 and had a surface area of 11,000 sq km before it broke apart into several small icebergs.

• Icebergs are traditionally named from the Antarctic quadrant in which they were originally sighted, then a sequential number, then, if the iceberg breaks, a sequential letter.

A natural phenomenon

• The Ronne Ice Shelf near the base of the Antarctic Peninsula is one of the largest of several enormous floating sheets of ice that connect to the continent’s landmass and extend out into surrounding seas.

• Periodic calving of large chunks of those shelves is part of a natural cycle.

• Some ice shelves along the Antarctic peninsula, farther from the South Pole, have undergone rapid disintegration in recent years, a phenomenon scientists believe may be related to global warming.

• Earth’s average surface temperature has gone up by 1 degree Celsius since the 19th century, enough to increase the intensity of droughts, heat waves and tropical cyclones.

• But the air over Antarctica has warmed more than twice that much.

• Antarctic ice shelves regularly lose large chunks to the sea even as fresh ice forms inland.

• A very large iceberg, A-68A, calved from Antarctica’s Larsen Ice Shelf in 2017. In November last year, it appeared to be on a collision course with a remote South Atlantic island home to thousands of penguins and seals, threatening to impede their ability to gather food. It broke up before it could cause any damage to the abundant wildlife in the British Overseas Territory of South Georgia.

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